The invention relates to a communication system, and more specifically relates to a method of monitoring the performance of an uplink control channel in a radiocommunications system.
As is well known, there are many types of mobile radiocommunications systems, with the GSM system being just one example. Such systems define channels, over which mobile stations can communicate with a network infrastructure. In GSM, and other cellular radio systems, mobile stations communicate with base stations. Again, in GSM, and other cellular radio systems, the available channels are divided into traffic channels and one or more control channels. A control channel is used for various control functions, while the traffic channels are used to carry the actual communications between the mobile stations and base stations.
In particular, mobile communication systems typically define an access channel, which mobile stations use to communicate with a base station in order to indicate that they wish to access the network. The access channel may be a random access channel (RACH), meaning that any mobile station can send an access request message at any time, as long as it believes that no other mobile station is sending such a message.
Thus, in order for the system to operate satisfactorily, with mobile station users being able to access the network as required, it is important that the access channel, amongst other things, works as intended.
WO96/31988 discloses a cellular communications network, in which the system generates reports on the available signal quality in a cell, and also examines statistics on the traffic in a cell.
These statistics can be used to try and identify undetected faults in a random access channel. For example, the system can indicate if traffic levels are lower than expected, which may indicate that mobile stations are not able to access the system normally, but may simply be a natural fluctuation. More detailed analysis may reveal that handovers into a cell are still occurring, but that no calls are being set up in the cell.
This may well indicate a malfunction in the uplink control channel or access channel, but the necessary statistical analysis will inevitably mean that the fault will only be detected after some considerable time.
Moreover, a statistic such as this might also arise from a different malfunction.
The present invention is concerned with a method of detecting faults on an uplink control channel, such as an access channel.
More specifically, a base station, or other network infrastructure component with a receiver for access requests, is provided with a separate receiver, which is adapted to detect and count access messages. The counted number of access messages is then compared with the number of access messages received by the first receiver. If the number of accesses received by the two receivers are significantly different, this may indicate a fault in the access channel.
This has the advantage that it allows the network operator to obtain information quickly about potential faults in the network.